The present invention relates to an apparatus for controlling the amount of alcohol and gasoline supplied to a mixed fuel engine, and more particularly to a fuel injection apparatus for obviating the problem of rough idling and stalling when an engine is in the warming up stages.
Applicant has previously proposed a fuel injection control device for improving the performance of a mixed fuel engine upon starting it (Japanese Patent Application Filing No. Sho 56-88811, Japanese Laid-Open Patent Publication No. Sho 57-206735). This prior device provided for gasoline, utilized as an auxiliary fuel, to be injected from an auxiliary fuel injection valve, installed in line with a surge tank, into an intake passage on the engine, when the temperature of the engine is lower than a predetermined temperature. This results in improved engine starting performance. However, the ratio of injected gasoline to alcohol is not dependent upon whether the engine is idling or not. Consequently, the engine may stall because of the lack of engine power, particularly when starting the engine. The engine may also run very rough when trying to drive the vehicle. Finally, the alcohol fuel is consumed at an unnecessarily high rate resulting in lower miles per gallon.